Abstract

G. Seyitođlu writes: Koçyigit et al. 1999 claim to present evidence for a short phase of N-S compression during the late Miocene to early Pliocene in western Turkey. They argue that this episode intervened betwen the main extensional phases responsible for the Gediz (Alaºehir) graben and hence for the host of related E-W grabens that comprise this exceptionally active region. Their evidence is that the Miocene-lower Pliocene Salihli group in the Gediz (Alaºehir) graben is folded, unlike the unconformably overlying Plio-Quaternary graben infill.

I would like to point out that previously published work on the Selendi and Uºak-Güre basins, located immediately to the north of Gediz (Alaºehir) graben, contradicts the regional claim of Koçyiđit et al. 1999. The stratigraphy of these two basins is well established, on the basis of K-Ar (biotite and whole rock) isotopic ages and palynological studies. In the Selendi and Uºak-Güre basins, the lower-middle Miocene Ýnay group is nearly horizontal (Seyitođlu 1997; Seyitođlu et al. 1997; Seyitođlu & Benda 1998). The short phase of regional late Miocene-early Pliocene N-S compression invoked by Kocyiđit et al. 1999 fails to account for the essentially undeformed nature of the Ýnay group.

I would also like to point out that Kocyiđit et al. 1999 have given insufficient acknowledgement to some of the earlier work in the region. For example, the Salihli group, and the Acidere, Göbekli and Asartepe formations, were described by Emre (1996) and it is not clear whetherKocyiđit et al. 1999 are using the earlier definitions of